1. Field of the Invention
The present invention relates to an automobile heating, ventilation, and air conditioning unit usually abbreviated to xe2x80x9cHVAC unitxe2x80x9d or to xe2x80x9cHVAC modulexe2x80x9d, and specifically to a one-box type automobile HVAC unit capable of being automatically controlled through either an electronic control unit (ECU) or an electronic control module (ECM), or a body control module or a body computer module (BCM).
2. Description of the Prior Art
In recent years, there have been proposed and developed various automobile heating, ventilation, and air conditioning (HVAC) systems whose automatic control can be achieved by an ECU/ECM coordinating all engine functions such as the fuel injection and ignition system or a BCM handling the functions of controlling such items as an electronic comfort control system or an electronic climate control system. A typical HVAC unit contained in the electronic climate control system (ECC system), is usually located substantially in the center of the front passenger compartment, and has at least a heating, ventilation, and air conditioning (HVAC) unit case, a blower fan unit, an evaporator core assembly, and a heater core assembly. The HVAC unit case defines therein an air mix chamber in which the evaporator core air (cold air introduced through a bypass air passage into the air mix chamber) and the heater core air (warm air) are properly blended, in dependence on the degree of air-mix-door opening. The amounts of blended air or conditioned air flowing through the vent outlet, the defroster outlet, and the foot vent outlets are adjusted by regulating the position of the respective control doors. The HVAC unit case has the vent, defroster, and foot vent outlets above the air mix chamber. On later model cars, in order to widen a foot space and a glove box of the front passenger compartment, an automotive HVAC unit of a comparatively short fore-and-aft dimension is often used. In such an automotive HVAC unit having a short fore-and-aft dimension, it is preferable to arrange an evaporator core assembly along a stream line of air discharged from a blower fan, so that the blower fan unit is less offset from the evaporator core assembly in the longitudinal direction of the vehicle. However, with this arrangement, there is a tendency that air discharged from the blower fan does not blow uniformly against the inflow face of the evaporator core. So, such a HVAC unit is equipped with a deflector vane in an air passage between the blower fan and the evaporator core to properly divert the course of a stream of air discharged from the blower fan by virtue of the deflector vane, so that uniform air blow against the inflow face of the evaporator is ensured. The use of the deflector vane results in increased air-flow resistance, thereby reducing a quantity of discharged air. The deflector vane itself functions as a factor for air-flow noise. Also, the provision of the deflector vane in the air passage between the blower and the evaporator complicates a mold structure for the HVAC unit case. Such HVAC units or HVAC systems have been disclosed in Japanese Patent Provisional Publication Nos. 9-99725, 9-267620, and 10-297249. Nowadays, for the purpose of health and cleanliness, the needs of addition of an air-purifying filter to the HVAC unit have built up. In general, the greater the durability or the air-purifying effect of the air-purifying filter, the larger the filter size. If an air-purifying filter as well as the previously-noted deflector vane is incorporated into the HVAC unit, an air-flow resistance (energy loss) may further increase during operation of the blower of the HVAC system. As a matter of course, a discharged-air quantity is also reduced. In addition to the above, in HVAC units, there is a possibility that part of cold air (evaporator core air) passing through the bypass air passage is undesiredly flown directly into the foot vent outlet. To prevent this, a so-called temperature-adjustment rib is often provided nearby the outlet of the bypass air passage. The temperature-adjustment rib is also effective to reduce fluctuations in temperature of air properly conditioned or temperature-adjusted within the air mix chamber. The provision of the temperature-adjustment rib results in increased air-flow resistance, thus somewhat reducing discharged-air quantity. In a similar manner as the deflector blade, the temperature-adjustment rib also functions as a factor for air-flow noise. The structure of a HVAC unit case having a temperature-adjustment rib as well as a deflector blade is more complicated. This increases total production costs of HVAC units. Furthermore, the foot vent duct, communicating the foot vent outlet, is usually fitted to the outer peripheral wall of the HVAC unit case so as to discharge or blow warm air into the foot space of the vehicle occupants. Although a rectangular cross section (or a boxy shape) is desirable as an ideal shape of the HVAC unit, the foot vent duct fitted to the outer peripheral wall of the HVAC unit serves as a factor for deformation of the whole shape of the HVAC unit case. This results in troublesome packaging.
Accordingly, it is an object of the invention to provide a heating, ventilation, and air conditioning unit for automotive vehicles that avoids the aforementioned disadvantages of the prior art.
It is another object of the invention to provide an air-purifying filter equipped automobile heating, ventilation, and air conditioning (HVAC) unit, being compact in size and light in weight, and ensuring uniform air blow against the inflow face of an evaporator core with an evaporator arrangement along a stream line of air discharged from a blower fan, and capable of reducing total air-flow resistance during operation of the blower while ensuring an adequate filtering area of an air-purifying filter.
It is a further object of the invention to provide an air-purifying filter equipped automobile heating, ventilation, and air conditioning (HVAC) unit, being compact in size and light in weight, and having a temperature-adjustment rib and a built-in foot vent duct structure, and enhancing installation flexibility.
In order to accomplish the aforementioned and other objects of the present invention, an automobile heating, ventilation, and air conditioning (HVAC) unit comprises a heating, ventilation, and air conditioning unit case permitting flow of interior air, a blower fan unit having at least a blower fan for introducing air into the unit case, an evaporator core assembly having an evaporator core disposed in the unit case for taking heat from the air discharged from the blower fan to produce cool air, a heater core assembly having a heater core disposed in the unit case downstream of the evaporator core for adding heat to the cool air to produce warm air, a bypass air passage bypassing the heater core, an air mix door disposed between the evaporator core and the heater core for controlling a percentage of the cool air passing through the bypass air passage and the warm air produced by the heater core, depending on a degree of opening of the air mix door, the unit case defining an upstream air duct in the unit case upstream of the evaporator core for routing the air discharged from the blower fan toward the evaporator core, and an air-purifying filter slanted and arranged in the upstream air duct, so that an upstream end of the air-purifying filter is supported by an upper supporting portion fixedly connected to the unit case for supporting the evaporator core and so that a downstream end of the air-purifying filter is located away from a lower end of the evaporator core.
According to another aspect of the invention, an automobile heating, ventilation, and air conditioning unit, comprises a heating, ventilation, and air conditioning unit case permitting flow of interior air, a blower fan unit having at least a blower fan for introducing air into the unit case, an evaporator core assembly having an evaporator core disposed in the unit case for taking heat from the air discharged from the blower fan to produce cool air, a heater core assembly having a heater core disposed in the unit case downstream of the evaporator core for adding heat to the cool air to produce warm air, a bypass air passage bypassing the heater core, an air-mix sliding door disposed between the evaporator core and the heater core for controlling a percentage of the cool air passing through the bypass air passage and the warm air produced by the heater core, depending on a degree of opening of the air-mix sliding door, and the unit case including a fan scroll casing accommodating the blower fan in the fan scroll casing, and a substantially rectangular parallelopiped portion extending in a downstream direction from an air outflow side of the fan scroll casing, the substantially rectangular parallelopiped portion being constructed by a pair of side walls, and a backward wall and a forward wall both connected to the side walls to form a U-turn air-flow passage, wherein the evaporator core is located upright at a U-turn portion of the U-turn air-flow passage, the heater core is dimensioned to be smaller than the evaporator core in both height and width dimensions and located upright and downstream of and substantially parallel to the evaporator core, and which further comprises at least one foot vent duct partitioned and formed in the unit case utilizing a dimensional difference between the evaporator core and the heater core and at least one temperature-adjustment rib inwardly projecting from an inner peripheral wall surface of the forward wall of the unit case above the heater core, and wherein the at least one temperature-adjustment rib is provided adjacent to a foot vent outlet communicating the at least one foot vent duct, so that the foot vent outlet faces to a space defined just downstream of the at least one temperature-adjustment rib.